The primary goal of the investigator is to study various aspects of the turnover of elastin in the mammalian system. The exerimental model used in these studies will be the pregnant rat uterus. This system synthesizes and degrades significant amounts of elasting within a relatively short period of time. Elastin turnover will be quantiated by desmosine analysis of blood and urine using a radioimmunoassay. Other studies will be conducted to determine the exact nature of the excreted desmosine containing elastin peptides. Antibodies to the peptides will be developed with the belief that assays for specific peptides may be of value for clinical studies as well as basic research. Monoclonal antibodies will be produced for both the desmosine and as basic research. Monoclonal antibodies will be produced for both the desmosine and desmosine peptides, a method we believe is essentiall to expand the many potential uses of this assay. A major research commitment will also be directed toward understanding the hormonal control of elastin turnover and regulation of tissue elastase. Very little information is available on the mechanism of mature elastin turnover in normal and disease states. We hope that these studies will contribute to an understanding of these processes and develop techniques that will be applicable to clinical studies on human subjects.